Topping of the gas turbine engine cycle is well-known in the art. U.S. Pat. Nos. 4,815,282, 5,471,834 and 5,692,372, for example, show the prior attempts at integrating gas turbine with cycle-topping devices, such as piston-type internal combustion engines and eccentric rotary engines such as the so-called Wankel engine. Such cycle topping devices promise much-improved fuel efficiency for the integrated engine. All of the integrated engines disclosed in the above mentioned patents require an intercooler to cool the air before it enters the compressor section of the engine. Such intercooler are know to be bulky, heavy, etc. and, thus, not ideal for airborne applications.
For gas turbines destined for airborne applications, integration must not only successfully address improvements in cycle efficiency, but also provide a compact and lightweight package, and preferably one which does not significantly alter the envelope required versus that of a regular (i.e. non-compounded) gas turbine engine. Prior art attempts have not been as successful in these areas, and hence there exists a need for improved compact devices which offer not only improved efficiency, but also better power density, reliability, operability and so on.
Various types of cycle topping devices are known, including both non-rotating and rotating types. The present application is particularly concerned with eccentric rotary machines of all types useful in providing cycle-topping benefits to a gas turbine engine. Examples are shown in U.S. Pat. Nos. 5,471,834, 5,522,356, 5,524,587 and 5,692,372, to name a few, though there are certainly others available as well, as will be well-understood by the skilled reader.